Browser download directory question

So i have a file i wish to download 3.1 gigs. I don't have enough space on my internal storage to download it. How can i change the download directory? I have been tinkering with about:config. I have changed "browser.download.dir" to "/sdcard/" and changed "browser.download.useDownloadDir" to true and false.. no matter what i do it keeps downloading the file to the default location. Is there something i am missing? If this isn't possible is there some work around? please help! thanks.

So i have a file i wish to download 3.1 gigs. I don't have enough space on my internal storage to download it. How can i change the download directory? I have been tinkering with about:config. I have changed "browser.download.dir" to "/sdcard/" and changed "browser.download.useDownloadDir" to true and false.. no matter what i do it keeps downloading the file to the default location. Is there something i am missing? If this isn't possible is there some work around? please help! thanks.